coconut head

1. Someone who is stupid or foolish. I wouldn't believe a word that comes out of that coconut head's mouth. Of course a coconut head like Bill would be pulling on a door marked "Push." Watch what you're doing, you coconut head—you nearly broke the machine!

2. offensive slang A racial epithet typically directed at people of African or Polynesian descent. Primarily heard in US. "Coconut-head" is something my Samoan friend has been called before. It's a stupid thing to call someone, but it's still really insulting.

use (one's) coconut

To use one's own intelligence and intellectual ability; to think logically and rationally. In this phrase, "coconut" refers to one's brain. Often said as an imperative. Come on, Dean, I know you can figure this out on your own. Use your coconut for a change! We'll have to really use our coconuts if we're going to have any hope of solving this supply issue.